/*
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  (C) Copyright 2004, Li Chunqiang (chunqiang_li@c-sky.com)
 *  (C) Copyright 2009, Hu Junshan (junshan_hu@c-sky.com)
 *  (C) Copyright 2009, C-SKY Microsystems Co., Ltd. (www.c-sky.com)
 *  
 */ 
 
#ifndef __CKCORE_UACCESS_H
#define __CKCORE_UACCESS_H

/*
 * User space memory access functions
 */
#include <linux/compiler.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <asm/segment.h>

#define VERIFY_READ	0
#define VERIFY_WRITE	1

/* We let the MMU do all checking */
static inline int access_ok(int type, const void * addr, unsigned long size)
{
    return (((unsigned long)addr < current_thread_info()->addr_limit.seg) && 
              ((unsigned long)(addr + size) < current_thread_info()->addr_limit.seg));
}

static inline int verify_area(int type, const void * addr, unsigned long size)
{
    return access_ok(type, addr, size) ? 0 : -EFAULT;
}

#define __addr_ok(addr) (access_ok(VERIFY_READ, addr,0))

extern int __put_user_bad(void);

/*
 * Tell gcc we read from memory instead of writing: this is because
 * we do not write to any memory gcc knows about, so there are no
 * aliasing issues.
 */

/*
 * These are the main single-value transfer routines.  They automatically
 * use the right size if we just have the right pointer type.
 *
 * This gets kind of ugly. We want to return _two_ values in "get_user()"
 * and yet we don't want to do any pointers, because that is too much
 * of a performance impact. Thus we have a few rather ugly macros here,
 * and hide all the ugliness from the user.
 *
 * The "__xxx" versions of the user access functions are versions that
 * do not verify the address space, that must have been done previously
 * with a separate "access_ok()" call (this is used when we do multiple
 * accesses to the same area of user memory).
 *
 * As we use the same address space for kernel and user data on
 * Ckcore, we can just do these as direct assignments.  (Of course, the
 * exception handling means that it's no longer "just"...)
 */

#define put_user(x,ptr) \
  __put_user_check((x), (ptr), sizeof(*(ptr)))

#define __put_user(x,ptr) \
  __put_user_nocheck((x), (ptr), sizeof(*(ptr)))

#define __ptr(x) ((unsigned long *)(x))

#define get_user(x,ptr) \
  __get_user_check((x), (ptr), sizeof(*(ptr)))

#define __get_user(x,ptr) \
  __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
	
#define __put_user_nocheck(x, ptr, size)                          	\
({                                                              	\
	long __pu_err=0;                                	            \
	typeof(*(ptr)) *__pu_addr = (ptr);             	                \
 	typeof(*(ptr)) __pu_val = (typeof(*(ptr)))(x);                  \
	if(__pu_addr){                                                  \
		__put_user_size(__pu_val, (__pu_addr), (size), __pu_err);   \
	}                                                               \
	__pu_err;                                       	            \
})

#define __put_user_check(x,ptr,size)                            	\
({                                                              	\
	long __pu_err = -EFAULT;                                	    \
	typeof(*(ptr)) *__pu_addr = (ptr);                  		    \
	typeof(*(ptr)) __pu_val = (typeof(*(ptr)))(x);                  \
	if (access_ok(VERIFY_WRITE, __pu_addr, size) && __pu_addr)      \
		__put_user_size(__pu_val, __pu_addr, (size), __pu_err);     \
	__pu_err;                                               		\
})

#define __put_user_size(x,ptr,size,retval)                      	\
do {                                                            	\
	retval = 0;                                             	    \
	switch (size) {                                                 \
		case 1: __put_user_asm_b(x, ptr, retval); break;   	        \
		case 2: __put_user_asm_h(x, ptr, retval); break; 	        \
		case 4: __put_user_asm_w(x, ptr, retval); break; 	        \
		case 8: __put_user_asm_64(x, ptr, retval); break; 	        \
		default: __put_user_bad();                      	        \
	}	                                                       		\
} while (0)

/*
 * We don't tell gcc that we are accessing memory, but this is OK
 * because we do not write to any memory gcc knows about, so there
 * are no aliasing issues.
 *
 * Note that PC at a fault is the address *after* the faulting
 * instruction.
 */
#define __put_user_asm_b(x, ptr, err)                        	\
do{                                                         	\
	int errcode;                                  	    	    \
	 __asm__ __volatile__(                      	    	    \
	         "1:     stb   %1, (%2,0)        \n"    	    	\
	         "       br    3f                \n"             	\
	         "2:     mov   %0, %3            \n"         	    \
	         "       br    3f            	\n"		       	    \
	         ".section __ex_table,\"a\"      \n"    	    	\
	         "       .long  1b,2b            \n"         	    \
	         ".previous                      \n"         	    \
	          "3:                            \n"         	    \
	         :"=r"(err), "=r"(x), "=r"(ptr), "=r"(errcode)  	\
	         :"0"(err), "1"(x), "2"(ptr), "3"(-EFAULT)      	\
	         : "memory");                                	    \
}while(0)

#define __put_user_asm_h(x, ptr, err)                        	\
do{                                                         	\
	int errcode;                                  	    	    \
	 __asm__ __volatile__(                      	    	    \
	         "1:     sth   %1, (%2,0)        \n"    	    	\
	         "       br    3f                \n"         	    \
	         "2:     mov   %0, %3            \n"         	    \
	         "       br    3f              	\n"         	    \
	         ".section __ex_table,\"a\"      \n"    	    	\
	         "       .long  1b,2b            \n"         	    \
	         ".previous                      \n"         	    \
	          "3:                            \n"         	    \
	         :"=r"(err), "=r"(x), "=r"(ptr), "=r"(errcode)      \
	         :"0"(err), "1"(x), "2"(ptr), "3"(-EFAULT)      	\
	         : "memory");                                	    \
}while(0)

#define __put_user_asm_w(x, ptr, err)                        	\
do{                                                         	\
	int errcode;                                  	    	    \
	 __asm__ __volatile__(                      	    	    \
	         "1:     stw   %1, (%2,0)        \n"    	    	\
	         "       br    3f                \n"         	    \
	         "2:     mov   %0, %3            \n"         	    \
	         "       br    3f                \n"         	    \
	         ".section __ex_table,\"a\"      \n"    	    	\
	         "       .long  1b,2b            \n"         	    \
	         ".previous                      \n"         	    \
	          "3:                            \n"         	    \
	         :"=r"(err), "=r"(x), "=r"(ptr), "=r"(errcode)  	\
	         :"0"(err), "1"(x), "2"(ptr), "3"(-EFAULT)          \
	         : "memory");                                	    \
}while(0)


#define __put_user_asm_64(x, ptr, err)                         	\
do{                                                             \
	int tmp;                                                    \
	int errcode;                                                \
	typeof(*(ptr)) src = ( typeof(*(ptr)))x;                    \
	typeof(*(ptr)) *psrc = &src;                                \
	                                                            \
	__asm__ __volatile__(                                       \
	        "1:   ldw     %3, (%1, 0)	  \n"                   \
	        "     stw     %3, (%2, 0)     \n"                   \
	        "2:   ldw     %3, (%1, 4)     \n"                   \
	        "     stw     %3, (%2, 4)     \n"                   \
	        "     br      4f              \n"                   \
	        "3:   mov     %0, %4          \n"                   \
	        "     br      4f              \n"	                \
	        ".section __ex_table, \"a\"   \n"                   \
	        "       .long   1b, 3b        \n"                   \
	        "       .long   2b, 3b        \n"                   \
	        ".previous                    \n"                   \
	        "4:                           \n"                   \
	        :"=r"(err), "=r"(psrc), "=r"(ptr), "=r"(tmp), "=r"(errcode) \
	        : "0"(err), "1"(psrc), "2"(ptr), "3"(0), "4"(-EFAULT) 	    \
	        : "memory" );                                       \
}while (0)

#define __get_user_nocheck(x, ptr, size)                       	\
({                                                             	\
	long  __gu_err;	     					                   	\
	__get_user_size(x, (ptr), (size), __gu_err);                \
	__gu_err;                                               	\
})

#define __get_user_check(x, ptr, size)                          \
({                                                              \
	int __gu_err = -EFAULT;	                                    \
	const __typeof__(*(ptr)) __user * __gu_ptr = (ptr);	        \
	if (access_ok(VERIFY_READ, __gu_ptr, size) && ptr)          \
		__get_user_size(x, __gu_ptr, (size), __gu_err);         \
	__gu_err;                                                   \
})

#define __get_user_size(x, ptr, size, retval)                   \
do {                                                            \
	switch (size) {                                             \
		case 1: __get_user_asm_common((x),ptr,"ldb",retval); break; \
		case 2: __get_user_asm_common((x),ptr,"ldh",retval); break; \
		case 4: __get_user_asm_common((x),ptr,"ldw",retval); break; \
	 	default:                                                \
			x=0;                                                \
			(retval) = __get_user_bad();                        \
	}                                                           \
} while (0)

#define __get_user_asm_common(x, ptr, ins, err)                 \
do{                                                             \
    int errcode;                                                \
    __asm__ __volatile__(                                       \
            "1:   " ins "   %1, (%4,0)      \n"                 \
            "       br    3f                \n"                 \
            /* Fix up codes */                                  \
            "2:     mov   %0, %2            \n"                 \
            "       movi  %1, 0             \n"                 \
            "       br    3f                \n"                 \
            ".section __ex_table,\"a\"      \n"                 \
            "       .long  1b,2b            \n"                 \
            ".previous                      \n"                 \
            "3:                            \n"                  \
            :"=r"(err), "=r"(x), "=r"(errcode)                  \
            :"0"(0), "r"(ptr), "2"(-EFAULT)                     \
            : "memory");                                        \
}while(0)

extern int __get_user_bad(void);


#define __copy_user(to, from, n)\
do{                                                             \
	int tmp;                                                    \
	__asm__ __volatile__(                                       \
	        "       cmpnei  %1, 0           \n"                 \
	        "       bf      4f              \n"                 \
	        "1:     cmpnei  %0, 0          \n"                  \
	        "       bf      4f              \n"                 \
	        "       ldb     %3, (%2, 0)     \n"                 \
	        "2:     stb     %3, (%1, 0)     \n"                 \
	        "       addi    %2,  1          \n"                 \
	        "       addi    %1,  1          \n"                 \
	        "       subi    %0,  1          \n"                 \
	        "       br      1b              \n"                 \
	        "3:     br      4f              \n"                 \
	        ".section __ex_table, \"a\"     \n"                 \
	        "       .long   2b, 3b          \n"                 \
	        ".previous                      \n"                 \
	        "4:                             \n"                 \
	        : "=r"(n), "=r"(to), "=r"(from), "=r"(tmp)          \
	        : "0"(n), "1"(to), "2"(from)                        \
	        : "memory" );                                       \
} while (0)

#define __copy_user_zeroing(to, from, n) \
do{                                                             \
	int tmp;                                                    \
	int nsave;                                                  \
	__asm__ __volatile__(                                       \
	        "       cmpnei 	%2, 0		    \n"	               	\
	        "       bf      5f              \n"                 \
	        "1:     cmpnei  %0, 0           \n"                 \
	        "       bf      5f              \n"                 \
	        "2:     ldb     %4, (%2, 0)     \n"                 \
	        "       stb     %4, (%1, 0)     \n"                 \
	        "       addi    %2,  1          \n"                 \
	        "       addi    %1,  1          \n"                 \
	        "       subi    %0,  1          \n"                 \
	        "       br      1b              \n"                 \
	        "3:     mov     %3, %0          \n"                 \
	        "       movi    %4, 0           \n"                 \
	        "4:     stb     %4, (%1, 0)     \n"                 \
	        "       addi    %1, 1           \n"                 \
	        "       subi    %3, 1           \n"                 \
	        "       cmpnei  %3, 0           \n"                 \
	        "       bt      4b              \n"                 \
	        "       br      5f              \n"                 \
	        ".section __ex_table, \"a\"     \n"                 \
	        "       .long   2b, 3b          \n"                 \
	        ".previous                      \n"                 \
	        "5:                             \n"                 \
	        : "=r"(n), "=r"(to), "=r"(from), "=r"(nsave), "=r"(tmp)   \
	        : "0"(n), "1"(to), "2"(from)		         	    \
	        : "memory" );                                       \
} while (0)

unsigned long __generic_copy_from_user(void *to, const void *from, 
		                                 unsigned long n);
unsigned long __generic_copy_to_user(void *to, const void *from, 
		                                 unsigned long n);

#define copy_from_user(to, from, n) __generic_copy_from_user(to, from, n)
#define copy_to_user(to, from, n) __generic_copy_to_user(to, from, n)

#define __copy_from_user(to, from, n) copy_from_user(to, from, n)
#define __copy_to_user(to, from, n) copy_to_user(to, from, n)

#define __copy_to_user_inatomic         __copy_to_user
#define __copy_from_user_inatomic       __copy_from_user

#define copy_to_user_ret(to, from, n, retval) \
	({ if (copy_to_user(to, from, n)) return retval; })

#define copy_from_user_ret(to, from, n, retval) \
	({ if (copy_from_user(to, from, n)) return retval; })

long strncpy_from_user(char *dst, const char *src, long count);
long __strncpy_from_user(char *dst, const char *src, long count);

/*
 * Return the size of a string (including the ending 0)
 *
 * Return 0 on exception, a value greater than N if too long
 */
long strnlen_user(const char *src, long n);

#define strlen_user(str) strnlen_user(str, 32767)

/*
 * Zero Userspace
 */
unsigned long clear_user(void *to, unsigned long n);

unsigned long __clear_user(void __user *to, unsigned long n);

struct exception_table_entry
{
	unsigned long insn;
	unsigned long nextinsn;
};

extern int fixup_exception(struct pt_regs *regs);

#endif /* _CKCORE_UACCESS_H */
